diff --git a/src/httpserver.cpp b/src/httpserver.cpp
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -39,7 +39,7 @@
 static const size_t MAX_HEADERS_SIZE = 8192;
 
 /** HTTP request work item */
-class HTTPWorkItem : public HTTPClosure {
+class HTTPWorkItem final : public HTTPClosure {
 public:
     HTTPWorkItem(Config &_config, std::unique_ptr<HTTPRequest> _req,
                  const std::string &_path, const HTTPRequestHandler &_func)
diff --git a/src/init.cpp b/src/init.cpp
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -139,7 +139,7 @@
  * the chainstate, while keeping user interface out of the common library, which
  * is shared between bitcoind, and bitcoin-qt and non-server tools.
  */
-class CCoinsViewErrorCatcher : public CCoinsViewBacked {
+class CCoinsViewErrorCatcher final : public CCoinsViewBacked {
 public:
     CCoinsViewErrorCatcher(CCoinsView *view) : CCoinsViewBacked(view) {}
     bool GetCoin(const COutPoint &outpoint, Coin &coin) const override {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -583,7 +583,7 @@
  * transactions and balances, and provides the ability to create new
  * transactions.
  */
-class CWallet : public CCryptoKeyStore, public CValidationInterface {
+class CWallet final : public CCryptoKeyStore, public CValidationInterface {
 private:
     static std::atomic<bool> fFlushScheduled;
 
@@ -1127,7 +1127,7 @@
 };
 
 /** A key allocated from the key pool. */
-class CReserveKey : public CReserveScript {
+class CReserveKey final : public CReserveScript {
 protected:
     CWallet *pwallet;
     int64_t nIndex;
diff --git a/src/zmq/zmqnotificationinterface.h b/src/zmq/zmqnotificationinterface.h
--- a/src/zmq/zmqnotificationinterface.h
+++ b/src/zmq/zmqnotificationinterface.h
@@ -13,7 +13,7 @@
 class CBlockIndex;
 class CZMQAbstractNotifier;
 
-class CZMQNotificationInterface : public CValidationInterface {
+class CZMQNotificationInterface final : public CValidationInterface {
 public:
     virtual ~CZMQNotificationInterface();